It’s one of my new favorite resources.

AIDS Virus (HIV), computer model, produced by Richard Feldmann, NIH Image Bank

Need a royalty-free, high-quality medical picture or illustration? Try one of the National Institutes of Health Photo Galleries. By nature of my role, I spend most of my time in the National Cancer Institute Visuals Online, but there are searchable galleries from the National Institute on Aging, the National Institute of General Medical Sciences, the National Center for Complementary and Alternative Medicine, and many more.

Because these images were created with government funding, they are now in the public domain and free for use. Be sure to credit the source, though.